Examples

If the senses of logical constants are individuated in this way by the conditions for their grasp, we can distinguish between truth-functionally equivalent constants with different meanings, like and “ ”, as defined below:

For the former approach, the problem was that the empirical legitimacy of statements obtained via indirect testing also transfered to any expressions that could be truth-functionally conjoined to them (for instance, by the rule of ˜or™-introduction).

Likewise, the distinction allows Abelard to define negation, and other propositional connectives, purely truth-functionally in terms of content, so that negation, for instance, is treated as follows: not-p is false/true if and only if p is true/false.

The reason why any reductive identification of final ends with any lower-level properties is bound to fail is that the ends possessed by organisms are holistic ends, and no lower-level description of a biological process, however complete it may be, can be equated in meaning with a holistic description of the same process, even if the two descriptions are truth-functionally equivalent.